Hi there, I am currently using a Dexcom G4 for 7 days and what I am finding frustrating is that my blood sugars are running high, which they have been, but there doesn’t seem to be any reaction to my bolus of humolog with meals or corrections. I have used my meter to treat not the CGM. What is going on??? I’m so frustrated with this CGM and it almost feels worse having this information then giving me more control, its making me anxious knowing that I am remaining high regardless of the humalog I’ve given myself. I don’t know what to do? Sometimes I’m high, sometimes I’m low…HELP!!!
Yeah. I was totally gobsmacked to realize that for some people getting a CGM works this way, but it can. You are certainly not the first who has voiced this … complaint ? about CGM. It’s one of the reasons I say you have to actually use CGM before you’ll know how well it works for you. (Though probably not the first reason which pops into people’s minds).
Since I can only understand what your are talking about from “the neck up”, I’m not sure what to say. On the one hand you can simply stop using the CGM. But, assuming your CGM results were an accurate picture of your BG and not a result of a bad site or calibration problems, then your BG will still be sometimes high, sometimes low. You just won’t know it any longer and, thus, won’t be in a position to try to address it.
If you want to try to figure out what is happening with your BG then I suggest you post more information. It’s hard to suggest things to try when we don’t even know what your experience level is or whether you are using MDI or an insulin pump. You also haven’t provided any information about how accurate your CGM results may be. Just because it’s a Dexcom doesn’t mean it is infallible, no?
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As @irrational_John said, more information is needed to help identify and fix the problem. When I did a 7-day CGM trial, I tested twice as much as usual to verify that the CGM results were accurate (they were) - then used the CGM data to learn some things about what I was doing to cause all the results.
First of all it’s not worth stressing about. (I know, easy for me to say!) The CGM is just a window that allows you to view the effects of insulin, eating, and exercise on your blood glucose. I understand the stress of looking at out-of-range numbers but the CGM is not the cause of them. And deciding to not pay attention to them is not an effective tactic.
The CGM, however, is an unparalleled tool for implementing changes that can control your BGs. Maybe the best way to look at the CGM numbers is that they are just numbers and not a judgement on your worth as a human being. Out-of-whack blood glucose is not something that can be fixed quickly. It takes curiosity, knowledge, persistence, and a good attitude.
Are you aware of your insulin to carb ratio (I:C) and your insulin sensitivity factor (ISF, used to bring down high BGs)? What are you using for basal insulin? Is it a pump or is it a long-acting insulin? When was the last time that you tested your basal insulin needs?
A CGM is just a dumb tool. It will not automagically (stolen from Brian) fix what ails you. It can be incredibly effective but that effectivity comes with knowledge and persistence.
I’ve had the experience of shooting a large correction bolus and then watch my blood glucose stubbornly remain high. It happens. I hated it! But the best thing to do here is not to get mad (or despair) but take action to lay a foundation to fix this for the long term. Have you read Scheiner’s Think Like a Pancreas? Perhaps gaining some more working knowledge of diabetes and insulin will be your best first move. Don’t give up! You can solve this puzzle but it will take some work and tenacity. I wish you well.
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I am currently not pumping and using MDI, I was told to “calibrate” the dexcom at least every 12 hours with a blood sugar check using my meter and to not treat using just the dexcom reading alone. So, if I am getting an alert, I check with my meter and confirm the accuracy (which it has been relevantly accurate) with my meter. I have been diabetic for 7 years, I was gestational diabetic (2004) with my daughter prior to being diagnosed in 2008. I have used the pump and then gone back to MDI. I was initially diagnosed Type 2, but then lost 80lbs and had no change in my insulin requirements, I then insisted on an endo referral and she tested me and I have antibodies, so now Type 1 (I guess, I don’t ever follow any criteria, haha). My I:C is 1:10 and my correction is 1:30 over 100. I have a different night time correction because I tend to have lows during the night. I take Levemir 34 units/twice daily. I don’t know my ISF. How do you test for that or basal insulin need?
The ISF or Insulin Sensitivity Factor is an attempt to characterize how much insulin is needed to correct for a high BG.
You said that you use a 1:30 ratio (over 100 mg/dl) to correct a high BG. By that I understand you to mean that if your BG was 205 and you wanted to correct to 100 you take (205 - 100) / 30 or 3.5 U of insulin. Correct? If so then your ISF is 30.
Could you throw some “for example” numbers at that? How closely do the SG (Sensor Glucose) readings on your Dexcom typically match to your BG (Blood Glucose) readings from your meter?
i am type 1 of LADA and using pump or MDI along with Dexcom G4. At the beginning of using Dexcom, i had same problem as your are to figure out CGM reading and to take action to adjust additional insulin or take sugar to normalize
my glucose level. So for i use following guidelines
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eat at least one meal with exact measurement of food which i know how much of cab, protein, fat. so i see the my Dexcom how to respond. With morning Dexcom calibration and injection and eating and go to working give me safe mode
to use my Dexcom reading. -
When my low sign of Dexcom give 45 arrow down with below 80mg/dl than take 15g of sugar wait 15 min what is my current Dexcom reading and trend determine next action . if i see the Dexcom is not change then check with glucose meter to see current reading is correct of malfunction of Dexcom.
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When i see the 90 up arrow after eating go out side work for 20 min.
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when i have to correction of high glucose level of Dexcom reading, i use glucose meter to check and compare with Dexcom reading because there is some kind of false reading of glucose reading if to much off then retest again glucose meter to determine how much of insulin i need along with insulin on board figure.
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never do correction injection base on Dexcom reading only
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Do the glucose meter testing with LAB make sure my glucose meter is in good and most accurate with LAB test result.
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Eat the reference food to check my current 1:C ratio, ISF number for different time line.
With Dexcom i find out more hidden my insulin respond and food behavior . With this additional information i manage my insulin injection time and food. I am so great to my Dr to give CGM to enjoy life without fear of glucose level problem.
PS: my A1C was 5.4~5.6 for last 3 year, last A1C was 6.4 due to my glucose meter was broken and could not find out until 2 month ago when i did LAB testing. Currently with new glucose meter and Dexcom data reading show estimate A1C is 5.3. i will to A1C again next month
Im new over here, but on a few of the other online Diabetes forums.
I have the G5 system, but that doesn’t matter for the sake of this conversation.
Ultimately, a CGM can’t and shouldn’t replace a standard glucometer. Maybe one day it will, but not anytime soon.
A few thoughts, some of which were already mentioned:
- I always try to calibrate the system when my blood sugar is most consistent, and you wouldn’t want to enter a calibration after eating.
-The system absolutely gets more accurate over time. The first 1-3 days of a new sensor are rarely precise. I try to keep the same sensor on for about 10-12 days solely for this reason.
-My glucometer (Accu-Chek Aviva Expert) is good at telling me what my blood sugar is. My Dexcom is good at telling me where my blood sugar as going (there’s a difference). The trend arrows rather than the actual number are what I worry about most with my CGM. For example, a 70 with a straight up arrow doesn’t concern me nearly as much as an 80 with a straight down arrow. Either way, I’m still using a test strip to confirm.
I hope this helps. My CGM setup is a DEXCOM G5, iPhone 6s, and Apple Watch
I encourage you to learn more about how diabetes and insulin interact. The book I suggested above is a good place to start. The effort expended to enhance your personal knowledge of diabetes will pay rich rewards in the long term. Gary Scheiner’s Integrated Diabetes website provides a good basal test protocol.
Most of his advice pertains to using an insulin pump but you can adapt this method using MDI. It will be hard to make adjustments to any of your other ratios if your basal insulin is not well calibrated.
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Would second he recommendation to read the book Think Like A Pancreas by Gary Scheiner. Will explain the ins and outs of how the different insulin work. And will show you step by step how to do the testing so you know your personal Duration of Insulin Activity, wether your basal insulin dose is lasting as long as you expect, What your insukin sensitivity factor is at various times of day and what your Insulin to carb ratios arm for various times of day.
Having a CGM makes it much easier to do all the testing required and is so worth it in your level of control. Likely your doc will look at the trial results and make some recommendations on changes BUT understanding and knowing how to do this for your self makes staying in top of all the changes that the D-life brings over time so much easier and a lot less stressful.
You can get the book for ereader from Amazon if you want it now. Is one of my go to D-bibles, and is written for the lay reader with a down home easy to understand style. Gary teaches you all the stuff you wished you Endo/CDE etc had from the beginning.
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For whatever its worth, note that you can probably also check it out from your local library. They most likely have the book. Just check their online catalog.
These days many libraries may also have the ebook version of “Think Like A Pancreas” available to be checked out. (The New York City public library, for example, has the ebook. Which is good for me since otherwise I am about 4 hours travel time from NYC 
)